Summary of work: Nutrition evaluation in the male and female participants of the Baltimore Longitudinal Study of Aging (BLSA) has been carried out by periodic collection of 7-day dietary diaries and by measurement of vitamin levels in plasma. The dietary technique has provided data over a 39 year period in men and a 19 year period in women. The ages of the participants range from 20 to 95 years. Since the BLSA is a multi- disciplinary study, it is possible to carry out correlations between nutritional intakes, and many other related variables, as well as a number of clinical outcomes. We are continuing the collection of 7-day food intake diaries in collaboration with USDA and HNRC scientists. We examined prospectively the relationship between dietary patterns and body composition among women and men participating in the Baltimore Longitudinal Study on Aging (BLSA) using cluster analysis. Our objective was to further elucidate the nutritional etiology of changes in adiposity over time as measured by body mass index and waist circumference using dietary patterning methods, specifically, cluster analysis. Many studies on dietary patterns have empirically derived a "healthy" type of dietary pattern that is relatively higher in fruits, vegetables, fiber, and other "healthy" foods. We hypothesized that a healthy dietary pattern would lead to smaller changes in body mass index and waist circumference compared to the other dietary patterns. We derived five dietary patterns, healthy, white bread, alcohol, sweet, and meat and potatoes. Mean annual change in BMI was 0.30 +/- 0.06 kilograms per squared meter for subjects in the meat and potatoes pattern compared to 0.05 +/- 0.06 kilograms per squared meter for those in the healthy pattern (P < 0.01). Mean annual change in waist circumference was more than three times greater for subjects in the white bread pattern (1.32 +/- 0.29 cm) compared to those in the healthy pattern (0.43 +/- 0.27 cm) (P < 0.05). Consuming a dietary pattern high in fruits, vegetables, reduced-fat dairy and whole grains and relatively low in red and processed meat, fast food, and soda may reduce increases in BMI and waist circumference. Given that foods are not consumed in isolation, dietary pattern research based on natural eating behavior may be useful in understanding dietary causes of obesity and helping individuals trying to control their weight.